MOCVD of Sr-containing oxides: transport properties and deposition mechanisms of the Sr(tmhd)2•pmdeta precursor

Metal-organic (MȮ)CVD processes adopting the Sr(tmhd) 2·pmdeta precursor have been investigated. In-situ Fourier-transform infrared spectroscopy (FTIR) monitoring has shown that Sr(tmhd)2·pmdeta possesses a low stability which precludes efficient sublimation/evaporation processes, and requires reactors equipped with a direct liquid injector (DLI) for suitable MOCVD processes. The deposition process results in the formation of polycrystalline SrO and/or SrCO3 films. The kinetics and the mechanism of film growth have been investigated combining in-situ FTIR techniques and ex-situ techniques for chemical and structural analyses - energy dispersive X-ray (EDX) microanalysis, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction(XRD). Precursor decomposition occurs above 300°C, leading to the formation of ketones and SrO films. Temperatures above 400°C and partial pressures above 9 mtorr favor a further oxidation/combustion of the ligand and its by-products, thus producing greater amounts of CO2, and hence of SrCO3.